The present invention relates to linear actuators in general, and more particularly to an apparatus for linearly displacing an output member in the form of a rope, cable or rod by means of a rotary prime mover, the coupling between the rotary prime mover and the output member being effected by flexible filamentary elements, such as small flexible cables or strings, being wrapped around the output member and applying a grip on the output member with a pull directed in an appropriate direction.
It is often desired to apply linear motion to an output member such as to displace the output member to an accurate position with force amplification from a prime mover to the output member.
The output member may be in the form of a rod which is reciprocated such as to reciprocate a utilization device, a slide for example, or it may be a closed loop member such as a conveyor belt or the like. The prime mover often is in the form of an electric motor, or a plurality of electric motors having a rotatably driven output shaft with the result that a rotary to linear motion transformer and force amplifier is required. The rotary to linear motion and force amplifier transformer means consists generally of a gear and rack structure, or similar arrangement.